Collapsible pneumatic structure



1 0- H. s; DIXON COLLAPS IBLE PNEUMAT I C S TRUC TUBE Filed Nov. '26,.1957

ATTOR/VEKS Patented Feb. 29, l

TATES PA'ra'r OFFICE Application November 26, 1937, Serial No. 176,765

I In Great Britain October 26, 1936 8 Claims.

This invention comprises improvements in and relating to pneumaticstructures or structural elements and is concerned with improvements infabric outer covers for the inflatable tubes for structures which may beerected or dismantled by inflation or deflation. The invention isapplicable to structures such as tents, awnings, temporary bridges,boats and other light portable structures, or pylons or poles forwireless aerials or other articles where inflatable tubes can besubstituted for wood or metal structures. In the inflated condition thefabric cover is liable to stretch and contract in various directionsaccording to the disposition of the warp and the weft, with the resultthat distortion occurs and the rigidity of the structure is impaired.

The object of the present invention is to provide an improvedconstruction of fabric outer cover which will be substantially free.from stretching or contraction and which will enable a very rigidarticle to be obtained in the inflated condition of the pneumatic memberwhich may be either straight or curved.

According to this invention the outer cover, made of fabric such ascanvas, is composed of longitudinal strips of which some have the weftrunning longitudinally and others have the warp running longitudinally.Thus, the tendency for stretching and contracting of one strip iscounteracted by the opposite dispositions of the warp and weft inanother strip, and a very rigid rodor core-like structure is providedwhen inflated. The cover advantageously comprises two halves joinedtogether along their longitudinal edges, one strip having the weftdisposed longitudinally of the tube and the other having the warpdisposed longitudinally of such tube. Naturally each strip may be madeup of a number of pieces of fabric joined end to end, according to thedesired length of the strip. If desired each strip may be composed of adouble layer of fabric to provide a two-ply strip, one layer of eachstrip having a longitudinal weft and the other layer having alongitudinal warp.

According to a modification, the object and purpose of the invention maybe achieved by the provision of longitudinal strips with the weftsrunning longitudinally, the strips having different textures so that onestrip has a flne weave and the other has a coarse weave.

In order to enable the invention to be readily understood reference willnow be made to the accompanying drawing illustrating two examples ofconstruction in which the weft and warp are conventionally represented.

In the drawing- Figure 1 is a perspective view illustrating part of apneumatic structure in the form of a rib for a tent, such rib beingshown inthe deflated condition,

Figure 2 is a cross section of the pneumatic rib shown in Figure 1, inthe inflated condition.

Figure 3 is a perspective view of a modified construction in thedeflated condition, and

Figure 4 is a cross section of the pneumatic structure of Figure 3, inthe inflated condition.

Referring to Figures 1 and 2 of the drawing, the pneumatic structurecomprises an inner tube a, made of indiarubber of flattened tubularsection, and an outer cover b made of fabric such as canvas, a nipple cbeing provided for inflating the inner tube. The outer cover b iscomposed of longitudinal strips d, e, the strip d having the weftrunning longitudinally and the strip e having a warp runninglongitudinally. The strips d, e are Joined along their edges by adhesiveand by rows of zig-zag stitching f, the two-longitudinal seams 9provided by the attachment of the strips to each other forming marginaledge portions which in the case of a tent, or boat for example, areutilised for the attachment of the panels or gores of the article. Thestrip d having the weft running longitudinally is less extensible thanthe strip e, so that'when the rib is inflated it presents a curved form.

The ends of the pneumatic structure may be closed by clamping jaws h kwhich may be tightened against each other by screwing up nuts i on boltsextending through holes in the canvas strips. The opening of these jawspermits rapid deflation of the rib. Except at its ends the outer coveris wider than the inner tube a to provide for the expansion of thelatter when inflated. At the ends its width is narrowed down to throatsof about the same width as the inner tube, by the provision of shortoblique lines of stitching I The clamping bolts a conveniently passthrough the canvas between the oblique and longitudinal lines ofstitching 1 f Ashort reinforcing length of fabric k may be eat securedby stitching-and 'adhesive around the I an inflatable support memberhaving a curved form in the inflated, erected condition of saidstructure or element, said member comprising an inflatable inner tube,and a fabric outer cover composed of a plurality of longitudinal stripsof inelastic woven material and of relatively narrow width compared withtheir length, some of said strips having the warp running longitudinallyand being disposed on one side of the curve of said member and the otherof said strips having the weft running longitudinally and being disposedon the other side of said curve, and said strips having marginal edgeportions joined together in adjacent strips by adhesive and by stitchingalong the inner boundary of saidmarginal portions so as to form atubular structure adaptedto deflnitely limit the inflation of said innertube.

2. A collapsible pneumatic structure comprising an inflatable supportmember having a curved form in the inflated, erected condition of saidstructure or element, said member comprising an inflatable inner tube,and a fabric outer cover composed of a plurality of longitudinal stripsof sides or the curve of said member and said strips having marginaledge portions Joined together in adjacent strips by adhesive and bystitching along the inner boundary. of said marginal portions so as toform a tubular structure adapted to deflnitely limit the inflation 01'said inner tube.

' strips being disposed respectively on opposite sides of said innertube and so that the strips with longitudinal warp are on one side ofthe curve of said member and the strips with longitudinal weft are onthe other side of the curve of said vmember, and said strips havingmarginal edge portions joined together in adjacent strips by adhesiveand by stitching along the inner boundary of said marginal portions soas to form a I tubular structure adapted to definitely limit the-inflation 01' said inner tube.

HENRY SECRETAN DIXON.

